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Question 1
Incorrect
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Cranial nerves VI, VII, VIII enter/exit the base of the brain at the:
Your Answer: Medulla
Correct Answer: Ponto-medullary junction
Explanation:Cranial nerves III, IV and V exit from the pons, VI, VII, VIII exit from the pontomedullary junction and cranial nerve IX, X, XI, XII exit from the medulla.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 2
Correct
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Which pair is correct concerning enteroendocrine cells in the GIT mucosa and their products?
Your Answer: D cells and somatostatin
Explanation:Somatostatin, an inhibitory hormone is secreted form the D cells of the Pancreatic Islets.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 3
Incorrect
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Ventricular depolarization plus ventricular repolarization is shown by the _____ interval
Your Answer: QRS
Correct Answer: QT
Explanation:The QT interval represents ventricular depolarization as well as ventricular repolarization.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 4
Incorrect
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The lamina propria contains all of the following except:
Your Answer: Plasma cells
Correct Answer: Neutrophils
Explanation:The connective tissue of the lamina propria is very loose, allowing it to be very cell rich. The cell population of the lamina propria is variable and can include, for example, fibroblasts, lymphocytes, plasma cells, macrophages, eosinophilic leukocytes, and mast cells. It provides support and nutrition to the epithelium, as well as the means to bind to the underlying tissue.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 5
Correct
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Where is the carotid sinus located?
Your Answer: After the bifurcation of the carotid artery, on the internal carotid
Explanation:The carotid sinus is a small dilation in the internal carotid artery just above its bifurcation into the external and internal carotid branch. Baroreceptors are present at this dilation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 6
Correct
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Select the correct statement regarding the portal vein.
Your Answer: It drains most of the gastrointestinal tract and the spleen.
Explanation:The portal vein supplies 75% of total blood flow to the liver and enters the liver centrally via the porta hepatis. Portal venous flow increases after meals. The portal vein receives blood from the intestines via the superior and inferior mesenteric veins, from the stomach via gastric veins and from the spleen and pancreas via the splenic vein.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 7
Correct
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Which of the following foods do NOT contain high levels of folate?
Your Answer: Yellow vegetables
Explanation:Folate naturally occurs in a wide variety of foods, including vegetables (particularly dark green leafy vegetables), fruits and fruit juices, nuts, beans, peas, dairy products, poultry and meat, eggs, seafood, grains, and some beers. Avocado, beetroot, spinach, liver, yeast, asparagus, and Brussels sprouts are among the foods with the highest levels of folate
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This question is part of the following fields:
- Haematology
- Medicine
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Question 8
Correct
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Which hormone secreting cell of the human anterior pituitary gland secretes growth hormone?
Your Answer: Somatotroph
Explanation:Somatotroph cells are responsible for the production of growth hormone. Somatotrophs occupy nearly 40% of the total surface area of the anterior pituitary, and they are acidophilic in nature.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 9
Correct
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The postextrasystolic potentiation of myocardial contractility is due to:
Your Answer: Increase in intracellular Ca2+
Explanation:The postextrasystolic potentiation of myocardial contractility Is not due to ventricular filling. It occurs in isolated locations in the heart and is due to increase availability of intracellular calcium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 10
Incorrect
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Empagliflozin was found to reduce the risk of cardiovascular deaths, non-fatal myocardial infarction and non-fatal stroke when added to standard treatment plans in patients with type 2 diabetes mellitus. This information was shared in 2015 by The New England Journal of Medicine and the results were expressed per 1000 patient years. In fact, empagliflozin had an event rate of 37.3/1000 patient years and placebo an event rate of 43.9/1000 patient years. How many patients who are at high cardiovascular risk need to be treated with empagliflozin to prevent a cardiovascular death, a non-fatal myocardial infarction or a non-fatal stroke?
Your Answer: 1000
Correct Answer: 150
Explanation:The number needed to treat (NNT) is an absolute effect measure that has been used to assess beneficial and harmful effects of medical interventions. In this case the NNT can be calculated as follows: NNT = 1/ Absolute risk reduction (ARR). ARR=(Control event rate expressed per 1000 patient years) – (Experimental event rate expressed per 1000 patient years) = 43.9-37.3 = 6.6/1000 patient yearsNNT=(Patient years)/ARR = 1000/ 6.6 = 151.5. The closest to 151.5 is 150, thus it is the correct answer.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 11
Incorrect
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What is the correct formula to calculate the positive predictive value?(TP = true positive; FP = false positive; TN = true negative; FN = false negative)
Your Answer: TN / (TN + FN)
Correct Answer: TP / (TP + FP)
Explanation:Positive predictive value is the probability that subjects with a positive screening test truly have the disease.Positive predictive value = true positive / ( true positive + false positive)
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 12
Incorrect
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Question 13
Incorrect
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Which of the following happens when anterograde neurons are stimulated?
Your Answer: Receptive relaxation of the git musculature
Correct Answer: Smooth muscle relaxation ahead of the stimulus
Explanation:Nitric oxide is thought to act as an anterograde neurotransmitter. Nitric oxide causes relaxation of smooth muscles ahead of the stimulus. Clinically it is used as a potent vasodilator.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 14
Incorrect
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The effects of β1 stimulation include the following
Your Answer: Increased Ca++ efflux from myocytes
Correct Answer: Increased strength of contraction
Explanation:β1 stimulation include the phosphorylation of L type Ca++ channels and phospholamban and increased Ca++ influx from myocytes.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 15
Correct
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Number of cases that are infected at a specific point in time
Your Answer: Prevalence
Explanation:Prevalence in epidemiology is the proportion of a population found to have a condition (typically a disease or a risk factor such as smoking or seat-belt use). It is arrived at by comparing the number of people found to have the condition with the total number of people studied, and is usually expressed as a fraction, as a percentage or as the number of cases per 10,000 or 100,000 people. Point prevalence is the proportion of a population that has the condition at a specific point in time. Period prevalence is the proportion of a population that has the condition at some time during a given period (e.g., 12 month prevalence), and includes people who already have the condition at the start of the study period as well as those who acquire it during that period. Lifetime prevalence (LTP) is the proportion of a population that at some point in their life (up to the time of assessment) have experienced the condition
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 16
Incorrect
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90% of erythropoietin necessary for haemopoesis is produced by the kidneys, the remainder is formed in the?
Your Answer: Spleen
Correct Answer: Liver
Explanation:Erythropoietin is produced by interstitial fibroblasts in the kidney in close association with peritubular capillary and proximal convoluted tubule. It is also produced in perisinusoidal cells in the liver. While liver production predominates in the fetal and perinatal period, renal production is predominant during adulthood.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 17
Correct
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A case-control study is being designed to look at the relationship between eczema and a new vaccine for yellow fever. What is the usual outcome measure in a case-control study?
Your Answer: Odds ratio
Explanation:A case–control study (also known as case–referent study) is a type of observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute. Case–control studies are often used to identify factors that may contribute to a medical condition by comparing subjects who have that condition/disease (the cases) with patients who do not have the condition/disease but are otherwise similar (the controls).An odds ratio (OR) is a statistic that quantifies the strength of the association between two events, A and B. The odds ratio is defined as the ratio of the odds of A in the presence of B and the odds of A in the absence of B or vice versa.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 18
Correct
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A 34 year old female presents to the clinic with skin tightness. On examination she has sclerodactyly, thickened skin of the shoulders and bi-basal crepitations. Her HRCT chest shows ground glass changes. Raynaud phenomenon is suspected and she is started on a monthly dose of IV cyclophosphamide (1 gm/month) for 6 months and a daily dose of 10 mg of oral prednisolone. However, she returned over a period of few weeks after developing exertional dyspnoea, pedal oedema and feeling unwell. On examination, JVP is raised, there is marked pedal oedema and bi basal crepitations on chest auscultation. Urine dipstick shows haematuria (++) and proteinuria (++). What in your opinion is the most likely cause of her deteriorating renal function?
Your Answer: Scleroderma renal crisis
Explanation:Scleroderma renal crisis (SRC) is a rare but severe complication in patients with systemic sclerosis (SSc). It is characterized by malignant hypertension, microangiopathic haemolytic anaemia with schistocytes and oligo/anuric acute renal failure. SRC occurs in 5% of patients with systemic scleroderma, particularly in the first years of disease evolution and in the diffuse form. Patients may develop symptoms of fluid overload.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 19
Incorrect
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Phosphate absorption in the proximal tubules is via which transporting molecule?
Your Answer: TRPV 5
Correct Answer: Na/Pi co transporter
Explanation:Sodium/phosphate cotransporters are located in the renal proximal tubular brush border, and are the key elements in proximal tubular phosphate reabsorption and phosphate homeostasis.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 20
Correct
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Which of the following does not lower ventricular rate in atrial fibrillation?
Your Answer: Adrenaline
Explanation:Adrenaline is a sympathetic neurotransmitter which increases the heart rate. During atrial fibrillation the atria is contracting at more than 200 beats/min. Acetylcholine is a parasympathetic neurotransmitter decreasing the heart rate. Digital also depresses the conduction at the AV conduction. Vagal discharge and occulocardiac reflux decrease the heart rate and convert the tachycardia into normal sinus rhythm.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 21
Incorrect
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The rate limiting pump in the HCL secretion is the?
Your Answer: Chloride/bicarbonate exchanger
Correct Answer: Hydrogen potassium ATPase
Explanation:The rate limiting pump in HCl secretion is the H+/K+ ATPase pump.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 22
Incorrect
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A 42 year old male arrives at the clinic due to cough and haemoptysis. Examination shows nasal mucosal ulceration. The doctor suspects Wegener's granulomatosis. Which anatomical area would be most commonly involved in this condition?
Your Answer: Kidneys
Correct Answer: Lungs
Explanation:Granulomatosis with polyangiitis (GPA, previously known as Wegener’s granulomatosis) is a systemic vasculitis that affects both small and medium-sized vessels. Patients typically initially suffer from a limited form that may consist of constitutional symptoms and localized manifestations such as chronic sinusitis, rhinitis, otitis media, ocular conditions. In later stages, more serious manifestations may arise, including pulmonary complications and glomerulonephritis, although the skin, eyes, and heart may also be involved but these lesions are less common. Diagnosis is based on laboratory testing (positive for PR3-ANCA/c-ANCA), imaging, and biopsy of affected organs, which demonstrate necrotizing granulomatous inflammation. GPA is treated with immunosuppressive drugs, typically consisting of glucocorticoids combined with methotrexate, cyclophosphamide, or rituximab. Relapses are common and the following systems are affected: Lower respiratory tract (95% of cases), renal involvement (80% of cases), skin lesions (45% of cases), ocular involvement (45% of cases) and cardiac involvement (33% of cases).
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 23
Incorrect
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Regarding the cardiac muscle striations as viewed under the microscope, which areas are dark?
Your Answer: H band and m line
Correct Answer: A band and z line
Explanation:Dark bands: a, h. Dark line: z. Clear band: i, m
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 24
Correct
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The motor speech area (Brocas Area) is:
Your Answer: Brodmann area 44
Explanation:A Brodmann area in the brain is defined by cytoarchitecture, histology and organization of cells:Primary Sensory 3,1,2Primary Motor 4Premotor 6Primary Visual 17Primary Auditory 41Brocas 44
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This question is part of the following fields:
- Medicine
- Neurology
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Question 25
Incorrect
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Nucleic acids are split into nucleotides in the:
Your Answer: Liver
Correct Answer: Intestine
Explanation:The pancreas is the major source for all the digestive enzymes including nucleases which split nucleic acids into nucleotides primarily in the small intestine.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 26
Incorrect
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Which of the following best describe N. Meningitides?
Your Answer: Anaerobe
Correct Answer: Gram negative cocci
Explanation:Neisseria meningitidis, often referred to as meningococcus, is a gram negative bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcaemia, a life-threatening sepsis. The bacterium is referred to as a coccus because it is round, and more specifically, diplococcus because of its tendency to form pairs. About 10% of adults are carriers of the bacteria in their nasopharynx.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 27
Incorrect
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Which of the following types of reactions are a part of the phase II metabolism of a drug?
Your Answer: Dealkylation
Correct Answer: Conjugation
Explanation:Drug metabolism can be broadly classified into:Phase I (functionalization) reactions: also termed non-synthetic reactions, they include oxidation, reduction, hydrolysis, cyclization and de-cyclization. The most common and vital reactions are oxidation reactions. (Of the given enzymes only Alcohol dehydrogenase is involved in phase I drug metabolism. Succinate dehydrogenase, is a vital enzyme involved in the Kreb’s cycle and the mitochondrial electron transport chain). They are mainly catalysed by Cytochrome P-450 enzyme.Phase II (conjugation) reactions: occur following phase I reactions, they include reactions: glucuronidation and sulphate conjugation, etc. They are mostly catalysed by UDP-glucuronosyltransferase enzyme. Other phase II enzymes include: sulfotransferases, N-acetyltransferases, glutathione S-transferases and methyltransferases.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 28
Incorrect
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The transport of the di- and tri-peptides into enterocytes is by:
Your Answer: Na+ dependent peptide transporter 1
Correct Answer: H+ dependent peptide transporter 1
Explanation:Peptides longer that four amino acids are not absorbed. There is abundant absorption of di and tri peptidases in the small intestine. They are absorbed into the epithelial cell of the small intestine via a transporter called Peptide Transporter 1 by co transport with H+ ions.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 29
Incorrect
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Renin is secreted by which of the following cells?
Your Answer: Collecting ducts
Correct Answer: Juxtaglomerular cells
Explanation:The juxtaglomerular cells are cells in the kidney that synthesize, store, and secrete the enzyme renin. They are specialized smooth muscle cells mainly in the walls of the afferent arterioles, and some in the efferent arterioles, that deliver blood to the glomerulus.
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This question is part of the following fields:
- Medicine
- Renal
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Question 30
Incorrect
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Question 31
Incorrect
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A patient with achalasia
Your Answer: Has failure of the lower oesophageal sphincter to contract.
Correct Answer: Has decreased production of vasoactive intestinal polypeptide (VIP)
Explanation:Oesophageal achalasia is an oesophageal motility disorder involving the smooth muscle layer of the oesophagus and the lower oesophageal sphincter (LES). It is characterized by incomplete LES relaxation, increased LES tone, and lack of peristalsis of the oesophagus (inability of smooth muscle to move food down the oesophagus) in the absence of other explanations like cancer or fibrosis. In achalasia, there is loss of nitric oxide (NO) and vasoactive intestinal polypeptide (VIP) releasing inhibitory neurons.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 32
Incorrect
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Regarding CSF:
Your Answer: Its volume is about 150ml – 500ml
Correct Answer: Disruption of arachnoid villi function results in a communicating hydrocephalus
Explanation:In normal adults CSF volume is around 125ml to 150ml. Turnover of the entire volume of cerebrospinal fluid is about 3 to 4 times a day. Composition of CSF is similar to that of plasma except that CSF is nearly protein-free compared with plasma and has different electrolyte levels. Blockage of the foramina causes an obstructive or non-communicating hydrocephalus. Communicating hydrocephalus or non-obstructive hydrocephalus is caused by impaired CSF reabsorption in the absence of any CSF flow obstruction.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 33
Incorrect
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Glucose absorption in the small intestine is coupled with which of the following electrolytes?
Your Answer: K
Correct Answer: Na
Explanation:Sodium-glucose linked transporter are family of proteins of different types. SGLT1 transporter is found in the intestinal mucosa of the small intestine and absorbs glucose via cotransport of Na+ ions.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 34
Incorrect
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Which of the following is an incorrect statement regarding the structure of DNA?
Your Answer: A nucleotide is a base joined to a sugar phosphate unit.
Correct Answer: The two strands of DNA are held together by cysteine bonds.
Explanation:The two strands of DNA are held together by hydrogen bonds formed between the nucleotide bases.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 35
Incorrect
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With regards to the function of the p53 protein produced by the p53 gene, which of the following statements is incorrect?
Your Answer: It is a nuclear transcription factor that increases production of a protein that enhances cell cycle enzymes
Correct Answer: It permits repair of mutations and other defects in RNA
Explanation:The p53 protein is a crucial tumor suppressor and plays several key roles in maintaining cellular integrity:
- Nuclear transcription factor: p53 is a nuclear transcription factor that regulates the expression of various genes involved in cell cycle control, DNA repair, apoptosis, and senescence.
- DNA repair: p53 permits repair of mutations and other defects in DNA (not RNA). It activates the transcription of genes involved in DNA repair mechanisms, allowing the cell to correct errors before proceeding with the cell cycle.
- Cell cycle regulation: p53 can induce the expression of p21, a protein that inhibits cyclin-dependent kinases, thereby halting the cell cycle at the G1/S checkpoint to allow time for DNA repair or to trigger apoptosis if the damage is irreparable. Mutations in p53 may fail to halt the cell cycle, allowing mutations to persist and potentially leading to cancer.
- Apoptosis: If DNA damage is extensive and cannot be repaired, p53 triggers apoptosis to prevent the propagation of damaged cells.
- Suppression of proto-oncogenes: p53 indirectly contributes to the suppression of proto-oncogenes by preventing the proliferation of cells with damaged DNA, thereby reducing the risk of oncogenic transformation.
Given these functions, the statement that p53 “permits repair of mutations and other defects in RNA” is incorrect, as p53 is primarily involved in the repair of DNA, not RNA.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 36
Incorrect
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What is the principle site of action of adrenocorticotrophic hormone (ACTH)?
Your Answer: Testes
Correct Answer: Adrenal gland
Explanation:Adrenocorticotropic hormone, also known as ACTH or corticotropin, is a polypeptide tropic hormone. It is synthesized by the corticotropic cells of the anterior pituitary. It works by regulating the secretion of glucocorticoid hormones from the cortex cells in the adrenal gland. It binds to the melanocortin (MC) 2 receptors on the surface of the adrenal zona glomerulosa cells, producing cortisol.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 37
Incorrect
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Question 38
Incorrect
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Which of the following limits the duration of inspiration and increases respiratory rate?
Your Answer: Nucleus of the tractus solitaries
Correct Answer: Pneumotaxic centre
Explanation:The mechanism of control of ventilation is an interplay of multiple regions in the brain. The medullary respiratory centre sets the basic rhythm of breathing and the pons modifies the output of the medullary centres. There are two pontine centres: apneustic and pneumotaxic.
The pnuemotaxic centre controls inspiratory time. Increased signals to this area increases respiratory rate. The dorsal respiratory group (DRG) integrates input from the stretch receptors and the chemoreceptors in the periphery and is composed mainly of inspiratory neurons. The DRG controls the basic rhythm of breathing by triggering inspiratory impulses. The ventral respiratory group (VRG) generates breathing rhythm and integrates data coming into the medulla and contains both inspiratory and expiratory neurons. They are primarily active in exercise and stress.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 39
Incorrect
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Humoral immunity is a major defence against:
Your Answer: Foreign or transplanted tissue
Correct Answer: Viral infections
Explanation:Humoral immunity is provided by the neutralizing and non-neutralizing antibodies that are formed from the B lymphocytes. This form of immunity is most important in viral infection. Non-neutralizing antibodies increases phagocytosis of the infected cell and inhibit the ability of the virus to replicate.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 40
Incorrect
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When oxygen supply is restored, lactate formed during anaerobic metabolism is converted back to?
Your Answer: Citrate
Correct Answer: Pyruvate
Explanation:During intense exercise, when the rate of demand for energy is high, glucose is broken down and oxidized to pyruvate, and lactate is then produced from the pyruvate faster than the body can process it, causing lactate concentrations to rise. The resulting lactate can be used in two ways:1. Oxidation back to pyruvate by well-oxygenated muscle cells, heart cells, and brain cells. Pyruvate is then directly used to fuel the Krebs cycle2. Conversion to glucose via gluconeogenesis in the liver and release back into circulation.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 41
Incorrect
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Where is most of the filtered sodium reabsorbed?
Your Answer: Collecting ducts
Correct Answer: Proximal tubule
Explanation:Renal reabsorption of sodium (Na+) is a part of renal physiology. It uses Na-H antiport, Na-glucose symport, sodium ion channels (minor). It is stimulated by angiotensin II and aldosterone, and inhibited by atrial natriuretic peptide. Most of the reabsorption (65%) occurs in the proximal tubule.
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This question is part of the following fields:
- Medicine
- Renal
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Question 42
Incorrect
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A 25-year-old student consumed a bottle of vodka at a party, the next day he finds that he feels excessively thirsty and is passing more urine than usual. Which of the following mechanisms best explains the polyuria due to excessive alcohol consumption?
Your Answer: Ethanol increases aquaporin proteins in the proximal convoluted tubule
Correct Answer: Ethanol inhibits ADH secretion
Explanation:Ethanol reduces the calcium-dependent secretion of anti-diuretic hormone (ADH) by blocking channels in the neurohypophyseal nerve terminal.Thus, ethanol’s inhibitory effect helps to explain the increased diuresis experienced during intoxicated states as well as increased free water loss; without appropriate ADH secretion, more water is excreted by the kidneys.Nausea associated with hangovers is mainly due to vagal stimulation to the vomiting centre. Following a particularly severe episode of alcohol excess, people may experience tremors due to increased glutamate production by neurons to compensate for the previous inhibition by ethanol.Management of alcoholism:Nutritional support: – Alcoholic patients should receive oral thiamine if their ‘diet may be deficient’.Pharmacological management:- Benzodiazepines for acute withdrawal- Disulfiram promotes abstinence – alcohol intake causes a severe reaction due to inhibition of acetaldehyde dehydrogenase. Patients should be aware that even small amounts of alcohol (e.g. In perfumes, foods, mouthwashes) can produce severe symptoms. Contraindications include ischaemic heart disease and psychosis.- Acamprosate reduces craving, known to be a weak antagonist of NMDA receptors, improves abstinence in placebo-controlled trials.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 43
Incorrect
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Which of the following derivatives of proopiomelanocortin is an opioid peptide?
Your Answer: ß lipotropin
Correct Answer: ß-endorphin
Explanation:ß-endorphin is an endogenous opioid neuropeptide which is mainly synthesized and stored in the anterior pituitary gland, derived from the precursor proopiomelanocortin (POMC). Some studies have shown that immune system cells are also capable of synthesizing ß-endorphin. β-endorphin is thought to exert a tonic inhibitory influence upon GNRH secretion and to be an important regulator of reproductive function.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 44
Incorrect
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Regarding Gene Knockout Mouse Models, all are true except:
Your Answer: RFLP can be sub categorised as slp( single locus proband mlp( multi locus probe).
Correct Answer: In knockout mouse models a gene is turned on through targeted mutation
Explanation:In knockout mouse models, a gene is not turned on but rather turned off or “knocked out” through targeted mutation. This involves disrupting or deleting the gene to study the effects of its loss of function. Knockout models are crucial for understanding the roles of specific genes, particularly those with unknown functions.
The other statements are true:
- Knockout models are important in studying the roles of sequenced genes with unknown function.
- RFLP (Restriction Fragment Length Polymorphisms) can be subcategorized as SLP (single locus probe) and MLP (multi locus probe).
- RFLP analysis is slow and cumbersome and is now largely obsolete, having been replaced by more efficient techniques.
- Sequence changes involved in RFLP can be analyzed more quickly by PCR (Polymerase Chain Reaction).
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This question is part of the following fields:
- Genetics
- Medicine
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Question 45
Incorrect
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The hepatic portal vein is a large vessel formed by which of the following veins?
Your Answer: The cystic vein
Correct Answer: All of the above
Explanation:The portal vein is usually formed by the confluence of the superior mesenteric and splenic veins and also receives blood from the inferior mesenteric, gastric, and cystic veins.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 46
Incorrect
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Choose the correct statement regarding trabecular bone:
Your Answer: Is made up of spicules/plates with a high surface to volume ratio, with many cells sitting on the surface of the end plates
Correct Answer: All of the options are correct
Explanation:Trabecular, spongy or cancellous bone. It is located inside the cortical bone and makes up around 20% of all bone in the body. It is made of spicules or plates with a high surface to volume ratio, where many cells sit on the surface of the end plates. It receives its nutrients from the extracellular fluid (ECF), exchanging about 10 mmol of calcium every 24 hours.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 47
Correct
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Which are the main hormones secreted by the posterior pituitary gland.
Your Answer: Oxytocin and vasopressin
Explanation:The posterior pituitary gland secretes oxytocin and vasopressin (antidiuretic hormone). These hormones are stored in Herring bodies before being secreted into the bloodstream.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 48
Incorrect
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Platelets are stored in this body organ.
Your Answer: Liver
Correct Answer: Spleen
Explanation:Megakaryocyte and platelet production is regulated by thrombopoietin. Each megakaryocyte produces between 1,000 and 3,000 platelets during its lifetime. An average of 1011 platelets are produced daily in a healthy adult. Reserve platelets are stored in the spleen, and are released when needed by splenic contraction induced by the sympathetic nervous system.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 49
Correct
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Activation of the cool receptor (CMR-1), causes:
Your Answer: Influx of Ca++ & Na+
Explanation:Cold and Menthol receptor 1 (CMR1) is a protein that in humans is encoded by TRPM8 gene. It is an ion channel which upon activation causes the influx of Na+ and Ca++ ions into the cell that leads to the depolarization and generation of an action potential.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 50
Incorrect
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In which cell would you find a Nissl body?
Your Answer:
Correct Answer: Bipolar neuron
Explanation:Nissl bodies are the structures of protein synthesis in neurones. They are granular bodies of Rough Endoplasmic Reticulum and ribosomes. Astrocytes, Microglia, Schwann cell, oligodendrocytes are collectively known as glia or supporting cells of the nervous system.
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This question is part of the following fields:
- Medicine
- Neurology
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SESSION STATS - PERFORMANCE PER SPECIALTY
